1. Field of the Invention
The present invention relates to a file management system and method for managing, in a centralized manner, two or more types of external memory devices for storing files, where the file management is in an electronic computer system connected to two or more types of external memory devices such as storage mediums, storage systems, etc.
2. Description of the Related Art
Conventionally, to improve functionality or to provide access to a greater quantity of data, a computer system may be connected to two or more types of external memory devices (e.g. a magnetic disk, a magneto-optic, a static memory, etc.) having different storage mediums, storage methods, access speeds, capacities, etc. In such a computer system, logical data blocks for managing files are stored in the respective external memory devices.
Since data blocks are provided in the respective external memory devices, the data blocks are not transmitted between the external memory devices. Thus, the external memory devices are individually controlled by the computer system.
As has been described above, in the computer system having two or more types of external memory devices, it is necessary to manage the data blocks in the external memory devices independently, complicating the processing required managing files.
Normally, a file comprises data blocks. Files are stored in a memory region of an external memory device in units of data blocks. When file management is performed in a data block unit of the file, processing can be executed only in the external memory device storing the file. It is not possible to perform flexible processing in a data block unit, which covers all connected external memory devices.
In addition, when all files stored in the external memory devices are totally managed, it is necessary to access all the connected external memory devices, read out file management information stored in the external memory devices, and carry out processing using a plurality of file management information units.